Vitamin and mineral supplements for human and veterinary use are commonplace. Recently, it has become recognized that certain groups of the human population may require quite high intakes of minerals, such as calcium, to prevent or alleviate certain disease states, for example, osteoporotic conditions. The medical management of certain anemias can be handled rather well by increasing the daily intake of iron. Some diets, or heavy physical exercise, may require the intake of considerable quantities of minerals apart from those generally obtained through what otherwise would be considered a balanced diet.
Mineral supplements, such as those commercially available, are useful in many circumstances where enhanced mineral uptake is desirable. However, adhering to a regimen which requires the separate intake of mineral supplements can give sub-optimal results, simply because the regimen requires a change in the normal habits and practices of the user. It would be more convenient if the minerals could be administered conjointly, so that they would be ingested without extra attention, planning and implementation on the part of the user.
It is particularly difficult to formulate mixtures of calcium supplements and iron supplements, inasmuch as these minerals tend to interact, which undesirably affects their nutritional bioavailability.
The depression of iron absorption by high levels of calcium was recognized as early as 1940. Since then, various groups have repeatedly confirmed the significant inhibition of iron absorption by calcium. Adverse effects of calcium, including decrease in hemoglobin regeneration, reduced whole body iron retention and delayed restoration of tissue and blood iron levels have been reported. In postmenopausal women, calcium supplements, namely, calcium carbonate and calcium hydroxyapatite, markedly reduced iron absorption. In addition, calcium carbonate in prenatal multivitamin mineral supplement was identified as an inhibitor absorption in nonpregnant women. Thus, individuals that consume high calcium and marginal amounts of iron simultaneously could develop iron deficiency anemia. See: Kletzein, S. W. (1940). Iron Metabolism. J. Nutr. 19, 187-97; Chapman, D. G. and Campbell, J. A. (1957). Effect of Calcium and Phosphorus Salts on the Utilization of Iron by Anemic Rats. Br. J. Nutr. 11, 127-133; Dunn, J. A. (1968). The Effects of Dietary Calcium Salts and Fat on Iron Absorption in the Rats. S. Afr. J. Med. Sci. 33, 65-70; Barton, J. C., Conrad, M. E. and Parmley, R. T. (1983). Calcium Inhibition of Inorganic Iron Absorption in Rats. Gastroenterology 84, 90-101; Dawson-Hughes, B., Seligson, F. H. and Hughes, V. A. (1986). Effects of Calcium Carbonate and Hydroxyapatite on Zinc and Iron Retention in Postmenopausal Women. Am. J. Clin. Nutr. 44, 83-88; and Seligman, P. A., Caskey, J. M., Frazier, J. L., Zucker, R. M., Podell, E. R. and Allen, R. M. (1983). Measurement of Iron Absorption from Prenatal Multivitamin Supplements. Obstetrics and Gyn. 61, 356-362.
It would be desirable, therefore, to have mixed calcium and iron supplements which are compatible and nutritionally available.
It is an object of the present invention to provide iron-plus-calcium mineral supplements which fulfill these unmet needs.
It is a further object of this invention to provide a method for fortifying foods, beverages and mineral supplement compositions with both iron and calcium.
These and other objects are secured herein, as will be seen from the following disclosure.